Compound pressure-engine.



v Patented luly I6, I90]. W L. WHITFIELD.

CUIW'IPOUND PRESSURE ENGINE.

(Application filed Apr. 15, 1899. Renewed Jan. 15, 1901.)

5 Sheets8heet L (No Mudal No. 678,806. Patented July n e, I901].

m. L. ll-ll'll'fl-BELD.

COMPOUND PRESSURE ENGINE.

I (Application filed Apr. 16, 1899. Renewed Jan..15, 1901.) Modem 5Sheets-Sheet 2.

Pa'tentadl lluly i6, I905. M. IL. WHBTHEIL'D. COMPUUND PRESSURE EMGIW.(Application filed Apr. 15, 1899. Renewed Jan. 15, 1901.

5 Shaets$heet 3.

(No Model.)

, Patented fluly as, won. M. L. WHITFIELD.

BOMPUUND PRESSURE ENGINE.

(Application filed Apr. 16, 1899. Renewed Jan. 15, 1901.)

5 shem shmm- (No Model.)

a e o 0 M W m: Nonms PETERS co moraumu. WASHINGTON a. c

No. 678,806. Patented July 16, neon m. L. WHITFIELD.

COMPOUND PRESSURE ENGINE,

(Application filed Apr. 15, 1899. Renewed Jan. 15, 1901.) (No Model.)

5 ShaetsSheet 5.

"ma NoRms wcrzns my, Movoumo" wnumovon, n. c.

IUNTTEE STaTEs PATENT EETEE.

MARCY L. WHITFIELD, OF MEMPHIS, TENNESSEE, ASSIGNOR TO THE WHITFIELDCOMPANY, OF SAME PLACE.

COMPOUND PRESSURE-ENGINE.

SPECIFICATION forming part of Letters Patent N 0. 678,806, dated July16, 1901. Application filed April 15, 1899, Renewed January 15, 1901.Serial No. 43,413. (No model.)

To all whom it may concern.-

Be it known thatI, MAROY L. WHITFIELD, a citizen of the United States,residing at Memphis, Shelby county, Tennessee, have invented certain newand useful Improvements in Compound Pressure-Engines, of which thefollowing is a specification.

My invention relates to improvements in compound steam-engines, and moreparticularly to that class of engines known as telescopic, andcomprising a stationary lowpressure cylinder, a stationarypiston-abutment, and a high-pressure piston-cylinder working on saidabutment and in said stationary cylinder, respectively; and my saidinvention has for its primary objects, first, to provide means wherebythe power of the engine is automatically increased either in starting,whereby the engine will accommodate itself to a maximum starting load,or in the event of a sudden overload being imposed thereon while inoperation to accommodate itself to the increased load; second, todispense with all stuffing-boxes, thereby decreasing leakage andlessening the friction, and, third, to simplify the general constructionof the engine, whereby its cost and weight may be reduced.

In accordance with the first object of my invention I control the mainor distributing valve by a governor, preferably a centrifugal governor,so that in starting or when a sudden load is imposed upon the enginelive steam will be admitted through the highpressure piston-cylinderdirectly into the lowpressure cylinder on the low-pressure stroke, andowing to the increased area of the lowpressure cylinder the admissionthereto of live steam will result in a very great increase of power onthe low-pressure stroke, enabling the engine to overcome the loadthereon in starting or to overcome a load greater than the normal loadwhen imposed on the engine during its operation, the engine in suchcases working as a semicompound engine.

I attain the second object of my invention by connecting the driving-rodwith arms secured to or formed integral with the highpressurepiston-cylinder. Steam working at all times on the cylinder side of thestationary abutment, there is no necessity for packing the connectionsbetween said piston-cylinder and the power-shaft.

The valve which I prefer to use in the stationary piston-abutment forcontrolling the admission and cut off of steam to and from thehigh-pressure cylinder is preferably a piston-valve whose stem does notrequire to be packed. The valve which I prefer to use for controllingthe admission of steam from the high to the low pressure cylinder andhereinafter referred to as the intermediate valve and located in thepiston-head of the high-pressure cylinder is preferably of thesemirotary type, its stem being splined to the exhaust-valve orotherwise constructed to rotate therewith, and as said stem Works at alltimes within the steam-space and has no connection with the atmosphereit also requires no packing. The exhaust-valve is also preferablyoscillating and is operated directly by connections with thepower-shaft, the only packing being that of the valve itself.Consequently in the construction of my engine no stuffing-boxes arenecessary.

The third object of my invention follows as a matter of course from theconstruction of the engine.

That my invention may be fully understood I will describe the same indetail, reference being had to the accompanying drawings, in which-Figure 1 is a side elevation of a compound engine embodying my presentimprovements. Fig. 2 is a horizontal section of the same. Fig. 3 is avertical longitudinal section. Fig. 4 is a cross-section on the line 44: of Fig. 3 looking in the direction of the arrow seen on thesection-line. Fig. 5 is a cross-section on the line 5 5 of Fig. 3looking in the direction of the arrow and illustrating partly the construction of the exhaust-valve with its operating mechanism; and Figs.6, 7, 8, and 9 are cross-sections on the lines 6 6, 7 7, 8 8, and 9 9,respectively, of Fig. 3.

In all of the above views corresponding parts are represented by thesame numerals of reference.

1 is a suitable frame, to which is bolted the low-pressure cylinder 2.Mounted in bearings 3 is the power-shaft 4, carrying one or morefly-wheels 5, two being shown.

Shaft 4 is provided with a crank 6, driven from the connecting-rod 7.Mounted to reciprocate in the cylinder 2 is the high-pressurepistoncylinder 8, working in said low-pressure cylinder 2. Thehigh-pressure piston-cylinder 8 is provided with two arms 9 9, workingin guides 10, which'are cast to the low-pressure cylinder 2, andconnecting said arms is a cross-head 11, (see Fig. 9,) having a wristpin 12 therein, on which the driving-rod 7 is mounted.

13 is the stationary piston-abutment, having two arms 14 14, bolted orotherwise secured to the engine frame 1. The highpressurepiston-cylinder 8 works on this stationary abutment, as shown. One ofthe arms 14 of the stationary abutment is provided with a live-steampassage 15, leading to a valve-chamber 16 therein. Mounted in saidvalve-chamberis the reciprocating main or distributing valve 17, thestem 18 of which is operated from a cross-head 19 by two arms 20 20. Thearms 20 connect with two rockerarms 21 on a rock-shaft 22, mounted inthe engine-frame. Keyed to the rock-shaft 22 is a lever 23, the upperend of which connects by an eccentric-rod 24 with an eccentric 25,whereby the operation of the eccentric will reciprocate the valve 17 inthe valve-chamber in the stationary abutment, as shown. The live-steampassage '15 leads into the valve-chamber 16 by means of a port 26, whichis at all times in connection with a pocket27in thedisiributing-valve17.Aport 28 leads through the stationary abutment, as shown,to permitlivesteam to drive the pistoncylinder backward within the low-pressurecylinder 2, the steam expanding against the stationary abutment, as willbe seen. The valve 17 is provided with a shoulder 29, adapted to closethe port 28 when expansion is to be effected from the high to the lowpressure cylinders when the engine is working compound. Said valve isalso provided with a passage 30, which is adapted to connect the pocket27 with the port 28 when the valve is moved to its forward limit in thevalve-cham ber in the direction of the shaft 4. This movement iseffected under the influence, preferably, of a cut-off governor 31 ofany suitable type, which controls the throw of the eccentric 25 todetermine the cut-off. WVhen the engine is stationary or working at avery slow speed, the pocket 27 will, through the passage 30, beincommunication with the port 28 on the low-pressure stroke to permitsteam to pass directly under boiler-pressure into the low-pressurecylinder; but as the speed increases the governor 31 will retard thecut-off, moving the valve 17 farther inward, so that the passage willnot communicate with the port 28. The cylinder-head 32 of thepistoncylinder is preferably removable, as shown, and is provided withan intermediate valve 33 therein, preferably of the oscillating orsemirotary type. Said valve is adapted to cover and uncover passages 34,which correspond, preferably, with passages 35 in the stationaryabutment, the latter passages conmeeting with the steam-passage 28. Theintermediate valve 33 is provided with pockets 36, which when theyregister with the passages 34 allow expansion to take place from thehighpressure to the low-pressure cylinder. The stem 37 of the valve 33is operated in any suitable way, but preferably from an exhaust-valve38. The stem 37 of the intermediate valve 33 is provided with a keyway39, (see Fig. 6,) in which a key (not shown) on the exhaust-valve 38works, whereby stem 37 may move longitudinally with respect to theexhaust-valve, but will be oscillated by the movements of the latter.

The exhaust-valve is provided with ports 40, adapted to register withports 41, connected with an exhaust-space 42, (see Fig. 5,) from whichleads an exhaust-pipe 43. The exhaustvalve may be operated in anysuitable way. I illustrate it as being provided with an arm 44, whichmay be moved up and down to oscillate the valve, said arm being operatedfrom a link 45, connected to a power-crank 46, the latter being operatedby a link 47 from the lower end of the lever 23. Preferably the arm 14of the stationary abutment opposite to the one containing the live-steampassages 15 is provided with a receiving-chamber 48, the purpose ofwhich is to allow for a sufficient steam-space in the engine for theaccumulation of steam therein, so that on running light and with thecut-off operating quickly the piston-cylinder will not be required tomove against a vacuum. Receivers for this purpose are common in compoundengines, although I am not aware that they have ever been placed so asto constitute an integral part of the device.

The operation of the engine is as follows: In starting, whether thehigh-pressure pistoncylinder is on the instroke or the outstroke, livesteam passes from steam pipe 15 and through port 26 into pocket 27 ofthe distributing-valve 17, thence through port 28 and passages 35 intothe high-pressure cylinder, the intermediate valve 33 being closed andthe exhaust-valve open, causing pistoncylinder 8 to make its instroke.As said piston-cylinder is about to reach the limit of its instroke, theconnections between the exhaust-valve 38 and the eccentric 25 will causesaid valve to close, and as said valve controls the intermediate valve33 the latter will open, allowing steam from the high-pressurepiston-cylinder to expand into the low-pressure cylinder. Owing,however, to the lagging of the cut-off the steam-passage 30 will be incommunication with port 35. Hence live steam will flow through thehigh-pressure cylinder directly intothe low-pressure cylinder from pipe15, through port 25, passage 30, port 28, and passage 35,. thencethrough ports 34 and the pockets 36 in intermediate valve to saidlow-pressure cylinder, the outstroke being effected under live-steampressure, and ow- IIO ing to the greater area of the low-pressurecylinder and its piston relatively to the area of the piston-abutmentthe power of the engine will be greatly increased. As the highpressurepiston-cylinder 8 reaches or is about to reach the limit of itsoutstroke the intermediate valve closes and the exhaust-valve opens,while the main or distributing valve again admits live steam to thehigh-pressure piston-cylinder 8, the engine Working semicompound. Thisoperation continues until the engine is running at the required speed,when themoment of cut-off is accelerated so that the passage 30 does notregister with the port 35, the shoulder 29 of the valve cutting off saidport on the low-pressure stroke, live steam being admitted to thehigh-pressure piston-cylinder 8, as before, to etfect the instroke; buton the outstroke the distributing-valve cuts oif the live steam at theport 35,the intermediate valve 33 opens, and steam from thehigh-pressure piston-cylinder eX- pands into the low-pressure cylinder,thus effecting the outstroke. As the high-pressure piston-cylinderreaches or is about to reach the limit of its outstroke, theintermediate valve closes and the exhaust-valve opens to exhaust steamfrom the low-pressure cylinder, while the distributing-valve will nowagain be in a position to admit live steam to the high-pressurecylinder, and so on, the engine working compound.

Should in starting the high-pressure piston-cylinder S be at any pointof its outstroke, the same operation as described will take place, livesteam being admitted to the high-pressure piston-cylinder.

Should during the normal operation of the engine an overload be imposedthereon, its speed will be reduced, so that on the outstroke of thehigh-pressu re piston-cylinder immediately following such reduction ofspeed live steam will be admitted to the low-pressure cylinder throughsaid high-pressure piston-cylinder, owing to the lagging of the cut off,exactly as in starting, whereby the available power of the engine isincreased to overcome the increase in the load thereon, the engineworking semicompound until it has again acquired its normal or regularspeed.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters Patent, is

1. In a compound engine, the combination with the high and low pressurecylinders, of means operating automatically under certain conditions andat a certain point of the stroke to establish direct communicationbetween the source of live-steam supply and the lowpressure cylinderthrough the high-pressure cylinder to change the operation of the enginefrom compound to semicompound, for the purpose set forth.

2. In a compound engine comprising a low pressure cylinder, apiston-abutment and a hi gh-pressure piston-cylinder workin g on saidabutment and in said low-pressure cylinder respectively; means operatingautomatically for establishing under certain conditions and at a certainpoint of the stroke, direct commu nication between the source oflive-steam supply and the low-pressu re cylinder through thehigh-pressure cylinder, to change the normal operation of the enginefrom compound to semicompound, for the purpose set forth.

In a compound engine comprising a lowpressure cylinder, apiston-abutment and a high-pressure piston-cylinderworking on saidabutment and in said low-pressure cylinder respectively; means operatingautomatically for establishingat a certain point of the stroke of thehigh-pressure cylinder in starting, direct communication between thesource of live-steam supply and the low-pressure cylinder through saidhigh-pressure cylinder, to change the normal operation of the enginefrom compound to semicom pound, for the purpose set forth.

4. In a compound engine comprising a lowpressure cylinder, apiston-abutment .and a high-pressure piston-cylinder working on saidabutment and in said low-pressure cylinder respectively; means operatingautomatically for establishing under certain conditions and at a certainpoint of the stroke during the normal operation of the engine, directcommunicat-ion between the source of live-steainsupply and thelow-pressu re cylinder through the high-pressure cylinder to change saidoperation from compound to semicompound,for the purpose set forth.

5. In a compound engine, the combination with the high and low pressurecylinders, a valve mechanism,and suitable steam passages and portscontrolled thereby and operating to cause the engine to normally workcompound; of means automatically changing the operation of the valvemechanism to establish, under certain conditions and at a certainpointof the stroke, direct communication between the source of live-steamsupply and the low pressure cylinder through the high-pressure cylinderto change said normal operation from compound to semicompound, for thepurpose set forth.

6. In a compound engine comprising high and low pressure cylinders, avalve controlling the flow of live steam to the high-pressure cylinder,a valve controlling a passage or passages leading from saidhigh-pressure cylinder into said low-pressure cylinder, and anexhaust-valve controlling the flow of steam from the low-pressurecylinder; at valve-gear operating the valves to cause the engine tonormallywork compound and means operat ing automatically for changingthe operation of the valve-gear and valves so as to establish, undercertain conditions and at a certain point of the stroke, directcommunication between the source of live-steam supply and thelow-pressure cylinder through the high-pressure cylinder to change thenormal operation of the engine from compound to semicompound, for thepurpose set forth.

IIO

7. In a compound engine comprising a lowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said low-pressure cylinder the purpose set forth.

8. In a compound engine comprising a lowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said low-pressure cylinder respectively a valve controlling theflow of live steam to the high-pressure cylinder, a valve controlling apassage or passages leading from the high-pressure cylinder into thelow-pressure cylinder, and an exhaust-valve for the latter cylinder;avalve-gear operating said valves to cause the engine to normally workcompound, and means automatically changing the operation of saidvalvegear and valves to establish, under certain conditions and at acertain pointof the stroke, direct communication between the source oflive-steam supply and the low-pressure cylinder through thehigh-pressure cylinder, to change the normal operation of the enginefrom compound to semicompound, for the purpose set forth.

7 9. In a compound engine comprising a lowpressure cylinder, apiston-abutment, ahighpressure piston cylinder working on said abutmentand in said low-pressure cylinder respectively, a valve controlling theflow of live steam to the high-pressu re cylinder, a valve controlling a:passage or passages leading from the high-pressure cylinder into thelow-pressure cylinder, andan exhaust-valve for the latter cylinder; avalve-gear operating said valves to cause the engine normally to workcompound, and means operating antomatically for changing the operationof said valve-gear and valves to establish, at a certain point of thestroke of the high-pressure cylinder in starting, direct communicationbetween the source of live-steam supply and the low-pressure cylinderthrough the highpressure cylinder, to change the normal operation of theengine from compound to semicompound, for the purpose set forth.

10. In a compound engine comprising alowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said low-pressure cylinder respectively, a valve controlling theflow of live steam to the high-pressure cylinder, a valve controlling apassage or passages leading from the high-pressure cylinder into the arests low-pressure cylinder and an exhaust-valve for the lattercylinder; a valve-gear operating said valves to cause the enginenormally to work compound, and means operating antomatically forchanging the operation of the valve-gear and valves to establish duringthe normal operation of the engine and at a certain point of the strokeof the high-pressure cylinder, direct communication between the sourceof live-steam supply and the lowpressure cylinder through thehigh-pressure cylinder, to change the normal operation of the enginefromcompound to semicompound, for the purpose set forth.

11. In a compound engine comprising a lowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said low-pressure cylinder, respectively, a valve controlling thesupply of live steam to the high-pressure cylinder, a valve controllingpassages leading from the high-pressure cylinder into the low-pressurecylinder, and an exhaust-valve for the latter cylinder; in combinationwith a valve-gear operated from a moving element of the engine andactuating the valves to cause the engine to normally work compound, and

means operating automatically for changing the operation of saidvalve-gear and valves so as to establish, under certain conditions andat a certain point of the stroke, direct communication between thesource of livesteam supply'and the low-pressure cylinder through thehigh-pressure cylinder, to change the normal operationof the engine fromcompound to semicomponnd, for the purpose set forth.

12. In a compoundengine comprising a lowpressure cylinder, apiston-abutment,a highpressure piston -cylinder working on said abutmentand in said low-pressure cylinder respectively, a valve controlling thesupply of live steam to the high-pressure cylinder, a valve controllingpassages leading from the high-pressure cylinder into the low-pressurecylinder, and an exhaust-valve for the latter cylinder; a valve-gearoperated from a mov-- ing element of the engine and actuatingthe valvesto cause the engine to normally work compound, a governor influencingthe operation of said valve-gear and valves so as to establish, undercertain conditions and at a certain point of the stroke, directcommunication between the source of live-steam supply and thelow-pressure cylinder through the high-pressure cylinder, to change thenormal operation of the engine from compound to semicompound, for thepurpose set forth.

13. In a compound engine comprisinga lowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said low-pressure cylinder respectively; a valve controlling thesupply of live steam to the high-pressure cylinder, a valve controllinga port or ports leading from said high-pressure cylinder into saidlowpressure cylinder, an exhaust-valve for the latter cylinder, a valvegear for operating said valves to cause the engine to normally workcompound, and a governor influencing the valve-gear and valves so as toestablish, a certain point of the stroke of the high-pressure cylinderin overcoming inertia or when the speed of the engine drops below anormal speed, direct communication between the source of live-steamsupply and the lo W-pressure cylinder through the high-pressure cylinderto change said normal operation from compound to semicompound, for thepurpose set forth.

let. In a compound engine comprising a power-shaft, a low-pressurecylinder, a piston-abutment, a high-pressure piston-cylinder connectedwith said power shaft and working on said abutment and in saidlowpressure cylinder respectively, a valve controlling the supply oflive steam to the high pressure cylinder, a valve controlling portsleading from said high-pressure cylinder into the low-pressure cylinder,and an exhaustvalve for the latter cylinder; a valve-gear, an eccentricon the power-shaft operating said valve-gear to cause the engine tonormally work compound, and a governor influencing the aforesaideccentric to change, under cert-ain conditions and a certain point ofthe stroke, the operation of the valve-gear and valves so as toestablish direct communication between the source of live-steam supplyand the low-pressure cylinder through the high-pressure cylinder tochange the normal operation of the engine from compound to semicompound,for the purpose set forth.

15. In a compound engine comprisinga lowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said low-pressure cylinder respectively, a valve in the head ofthe abutment controlling the supply of live steam to the high-pressurecylinder, a valve in the head of the latter cylinder controlling portsleading therefrom into the low-pressure cylinder, and an exhaust-valvein the head of said low-pressure cylinder controlling a passage or portleading therefrom; a valve-gear operating the aforesaid valves to causethe engine to normally work compound and means operating automaticallyfor changing the operation of the valve-gear and valves to establish,under certain conditions and at a certain point of the stroke, directcommunication between the source of live-steam supply and thelow-pressure cylinder through the high-pressure cylinder to change saidnormal operation of the engine from compound to semicompound, for thepurpose set forth.

16. In a compound engine comprisinga lowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said low-pressure cylinder respectively, a distributing-valve inthe head of said abutment controlling a supply of live steam to thehigh-pressure cylinder, an oscillating intermediate valve in the head ofthe latter cylinder controlling a port or ports leading therefrom intothe low-pressure cylinder, a rocking exhaust-valve in the head of saidlow-pressure cylinder and means for oscillating the intermediate valvethrough the exhaust-valve; a rock-shaft, connections between the sameand the distributing and exhaust valves and means for rocking saidshaft, for the purposes set forth.

17. In a compound engine comprising a power-shaft, a low-pressurecylinder, a piston-abutment, a high-pressure piston-cylinder working onsaid abutment and in said low-pressure cylinder respectively, a distributing-valve in the head of said abutment controlling the supply of livesteam to the highpressure cylinder, an oscillating intermediate valve inthe head of the latter cylinder controlling a port or ports leadingtherefrom into the low-pressure cylinder; a rocking exhaustvalve in thehead of said low-pressure cylinder and means for oscillating theintermcdiate valve through the exhaust-valve; a roclc shaft, connectionsbetween the same and the distributing and exhaust valves, an eccentricon the power-shaft connected with said rockshaft and operating thevalves to cause the engine to normally work compound, and a governorinfluencing the eccentric under certain conditions to change theamplitude of the rocking movements of the rock-shaft and therethroughthe operation of the distributing-valve to establish directcommunication between the source of live-steam supply and thelow-pressure cylinder at a certain point of the stroke of thehigh-pressure cylinder to change the said normal operation of the enginefrom compound to semicompound, for the purposes set forth.

18. In a compound engine comprising alowpressure cylinder, apiston-abutment, a highpressnre piston cylinder working on said abutmentand in said low-pressure cylinder, a cylindrical endwise-movabledistributingvalve in the head of the abutment and controlling the supplyof live steam to the highpressure cylinder, a discoidal oscillatingintermediate valve in the head of said highpressure cylinder controllinga port or ports leading therefrom into the low-pressure cylinder, acylindrical rocking exhaust-valve in the head of the low-pressurecylinder and means for oscillating the intermediate valve through theexhaust-valve; a rock-shaft and suitable connections between the sameand the distributing and exhaust valves for imparting the describedmovements thereto, substantially as set forth.

19. In a compound engine comprising a power-shaft, alo w-pressurecylinder, apistonabutment, a high-pressure piston-cylinder working onsaid abutment and in said lowpressure cylinder, a cylindricalendwise-movable distributing-valve in the head of the abutment andcontrolling the supply of live steam to the high-pressure cylinder, adiscoidal oscillating intermediate valve in the governor influencing theeccentric under certain conditions to vary the amplitude of the rockingmotion of the rock-shaft and change the operation of thedistributing-valve so as to establish at a certain point of the strokeof the high-pressure cylinder direct communication between the source oflive-steam supply and the low-pressure cylinder to change said normaloperation of the engine from compound to semicompound, substantially asand for the purposes set forth.

20. Ina compound engine comprisinga lowpressure cylinder, apiston-abutment, a highpressure cylinder working on said abutment and insaid low-pressure cylinder respectively said abutment having formedtherein a livesteam passage and two chambers one for the reception ofthe distributing-valve and the other serving as receiver, for thepurpose set forth.

21. In a compound engine comprising alowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said low-pressure cylinder respectively, said abutment havingformed therein a live-steam-supply passage and two concentric chambersof different areas, the outer chamber of greatest area acting as areceiver and the inner chamber of least area for the'reception of thesteam-distributing valve, and means for draining the-receiving-cham-'ber, substantially as and for the purpose set forth.

22. In a compound engine comprising a power-shaft, a low-pressurecylinder, a pistonabutment andahigh-pressure piston-cylinder working onsaid abutment; a pair of guideblocks in extension of the high-pressurecylinder, guides for guiding said blocks, a crosshead to which saidguideblocks are connected, and a driving rod connecting the oross-headwith a crank on the power-shaft, substantially as set forth.

23. In a compound engine comprising a power'shatt, a low-pressurecylinder, a pistonabutment, and a high-pressure piston-cylinder; guidescarried by the low-pressure cylinder in extension thereof, a pair ofguide-blocks carried by the high-pressure cylinder in extension thereof,a cross-head to which said guide-blocks are connected, and a drivingrodconnecting said cross-head to a crank on the power-shaft, substantiallyas described.

24. In a compound steam-engine, a lowpressure cylinder, apiston-abutment, a highpressure piston-cylinder working on said abutmentand in said low-pressure cylinder, said high-pressure piston-cylinderextended for connection with the crank-shaft beyond the steam areadetermined by the packing on said abutment; a self-packingdistributingvalve working in a suitable chamber and having'itsoperating-stem located externally-of said chamber for connection withthe valveoperati'ng device, an intermediate valve in the head ofthehigh-pressure piston-cylinder, an exhaust-valve for the low-pressurecylinder and the valve-stem for said intermediate valve operated by saidexhaust-valve located wholly within the steam area of the low-pres surecylinder, said exhaust-valve having its stein externally of said steamarea, substantially as set forth and for the purpose of dispensing withstu fling-boxes and glands for said parts.

25. In a compound steam-engine, a lowpressure cylinder, apiston-abutment, a highpressure piston cylinder working on said abutmentand in said 1ow-pressure cylinder, said high-pressure piston-cylinderextended for connection with the crank-shaft beyond the steam areadetermined by the packing on said abutment; a self-packingdistributingvalve working in a chamber and in the abutment, said valvehaving its operating-stem located externally of the valve-chamber andhigh-pressure piston-cylinder for connection with the valve-operatin gdevice, a semirotary expansion-valve in the head of the high-pressurepiston-cylinder, a semirotary exhaustvalve for the low-pressurecylinder, and the valve-stem for the expansion-valve splined to saidexhaust valve and located wholly within the steam area of thelow-pressure cylinder, said exhaust-valve having its stem externally ofsaid steam area, substantially as set forth and for the purpose ofdispensing with stuffing-boxes and glands for said parts.

This specification signed and witnessed this 20th day of March, 1899.

MARGY L. WHITFIELD.

Witnesses:

J NO. R. TAYLOR, ARCHIBALD G. REEsE.

